Null Hypothesis: There is no significant difference between the banding patterns and shell colour in different snail populations.
Alternative Hypothesis: There is a significant difference between the banding patterns and shell colour in the different snail populations.
Sampling Design:
Independent Variable: Habitat location Dependent Variable: Banding patterns and shell colour of snail in the different snail populations.
Initial Method: Collect a snail sample of 20 snails from high altitude - trees, medium altitude-bushes and 20 snails from low altitude- grassland, with a distance of 20 metres between each location using tape measure. Observe banding patterns and record your findings. Assuming that the snails move relatively short distances in their lifetime, the snail sampled at the different altitudes should be different populations.
Control:
Collect a snail sample of 20 each from the same gradient and the same distance of 20 metres in-between the same locations using a tape measure.
Observe banding patterns and record your findings.
To try to eliminate variables such as light intensity and temperature, the snails will be collected during the same season and same time of day. Again assuming that the snails move a relatively short distances in their life time, their populations should be distinct and pseudo-replication is hoped to be avoided simultaneously.
Locations:
1. Woodland-High Altitude
2. Bushes- High Altitude
3. Grassland- High Altitude
4. Woodland Low Altitude
5. Bushes- Low Altitude
6.Grassland: Low Altitude Figure 1: this shows the original map where the snails populations would be collected from Improved map: Figure 2: This shows the new locations the snails population will be collected from upon delibration
Improved Locations:
A:Shrubs- Medium Altitude
B: Shrubs-Medium Altitude
C: Shrubs- Medium Altitude
D: Woodland Medium Altitude
E: Woodland-Medium Altitude
F: Woodland:Medium Altitude
Improved Method: Collect a snail sample of a total of 150 snails. 75 of the snails will be collected from three different locations in the woodland area with 25 snails in each group.The distance will be 40 metres apart (in an attempt to avoid pseudorepliction) and aim for replication. Then the remaining 75 will be collected from shrubs with 25 snails in each snail population, in the exact same method as woodland. The phenotypic properties of the six snail populations are then recorded, and the result will be statistically analysed. The snail found are put in a pile to avoid picking the same snail up twice, then placed back where they were found afterwards. The same individuals pick up the snails in each location
Control:
The altitude should be kept the same when the population were collected from the six locations
The distance of 40 metres should be counted in steps by one individual to reduce variation in distance
To try to eliminate variables such as light intensity and temperature, the snails will be collected during the same season and same time of day.
INTRODUCTION While it is understood that many evolutionary processes are involved in genetic polymorphism, identifying which process plays the relative dominant role in maintaining polymorphism has been a popular topic of debate among the scientific community. (Jones et Al).Thus the aim of this investigation is to get an insight into whether the phenotypic variation between different populations of the western European snail species Cepaea nemoralis within the two specific locations, shrubs and the woodland, has been due to selection or a random process such as genetic drift.
Cepaea nemoralis commonly known as the grove snail is a terrestrial pulmonate gastropod mollusc that has been extensively studied for evolutionary research. In addition to the polymorphic properties presented by the variation in shell colour (mainly yellow, pink or brown) and banding pattern (the appearance of up to five dark bands), its relatively short migration distance per generation makes it easier to differentiate between the different populations and thus reduce the effects of pseudo replication, making C. Nemoralis a model organism.
We decided to sample C.nemoralis of the Pulpit Wood Reserve near Monks Risborough from three separate locations for woodland and grassland, with a minimum distance of 40 m between each locations. We attempted to control variables such as altitude, moisture and the people sampling the snails to ensure replication of each of the two habitats and to minimise pseudo replication that may be caused by close proximity. In addition, we had a sample size of 25 from each of the six locations to ensure good replication and representation of the populations in each given loci.
While the null hypothesis stated there was no significant difference in the frequency of phenotypes between the snail populations found in our two sampling locations, our alternative hypothesis states that there is a significant difference between the differences in shell colour and shell pattern between snail population in woodland and shrubs, The samples were collected and statically analysis was performed to produce data which would identify if the null hypothesis was true or very unlikely.
References: Jones, J. S., B. H. Leith, and P. Rawlings. "Polymorphism in Cepaea: A Problem with Too Many Solutions?" Annual Review of Ecology and Systematics 8.1 (1977): 109-43. Web. 12 Nov.
Group 10
Members:Hypothesis
Null Hypothesis: There is no significant difference between the banding patterns and shell colour in different snail populations.
Alternative Hypothesis: There is a significant difference between the banding patterns and shell colour in the different snail populations.
Sampling Design:
Independent Variable: Habitat locationDependent Variable: Banding patterns and shell colour of snail in the different snail populations.
Initial Method: Collect a snail sample of 20 snails from high altitude - trees, medium altitude-bushes and 20 snails from low altitude- grassland, with a distance of 20 metres between each location using tape measure. Observe banding patterns and record your findings.
Assuming that the snails move relatively short distances in their lifetime, the snail sampled at the different altitudes should be different populations.
Control:
Collect a snail sample of 20 each from the same gradient and the same distance of 20 metres in-between the same locations using a tape measure.
Observe banding patterns and record your findings.
To try to eliminate variables such as light intensity and temperature, the snails will be collected during the same season and same time of day. Again assuming that the snails move a relatively short distances in their life time, their populations should be distinct and pseudo-replication is hoped to be avoided simultaneously.
Locations:
1. Woodland-High Altitude
2. Bushes- High Altitude
3. Grassland- High Altitude
4. Woodland Low Altitude
5. Bushes- Low Altitude
6.Grassland: Low Altitude
Figure 1: this shows the original map where the snails populations would be collected from
Improved map:
Figure 2: This shows the new locations the snails population will be collected from upon delibration
Improved Locations:
A:Shrubs- Medium Altitude
B: Shrubs-Medium Altitude
C: Shrubs- Medium Altitude
D: Woodland Medium Altitude
E: Woodland-Medium Altitude
F: Woodland:Medium Altitude
Improved Method: Collect a snail sample of a total of 150 snails. 75 of the snails will be collected from three different locations in the woodland area with 25 snails in each group.The distance will be 40 metres apart (in an attempt to avoid pseudorepliction) and aim for replication. Then the remaining 75 will be collected from shrubs with 25 snails in each snail population, in the exact same method as woodland.
The phenotypic properties of the six snail populations are then recorded, and the result will be statistically analysed.
The snail found are put in a pile to avoid picking the same snail up twice, then placed back where they were found afterwards.
The same individuals pick up the snails in each location
Control:
INTRODUCTION
While it is understood that many evolutionary processes are involved in genetic polymorphism, identifying which process plays the relative dominant role in maintaining polymorphism has been a popular topic of debate among the scientific community. (Jones et Al).Thus the aim of this investigation is to get an insight into whether the phenotypic variation between different populations of the western European snail species Cepaea nemoralis within the two specific locations, shrubs and the woodland, has been due to selection or a random process such as genetic drift.
Cepaea nemoralis commonly known as the grove snail is a terrestrial pulmonate gastropod mollusc that has been extensively studied for evolutionary research. In addition to the polymorphic properties presented by the variation in shell colour (mainly yellow, pink or brown) and banding pattern (the appearance of up to five dark bands), its relatively short migration distance per generation makes it easier to differentiate between the different populations and thus reduce the effects of pseudo replication, making C. Nemoralis a model organism.
We decided to sample C.nemoralis of the Pulpit Wood Reserve near Monks Risborough from three separate locations for woodland and grassland, with a minimum distance of 40 m between each locations. We attempted to control variables such as altitude, moisture and the people sampling the snails to ensure replication of each of the two habitats and to minimise pseudo replication that may be caused by close proximity. In addition, we had a sample size of 25 from each of the six locations to ensure good replication and representation of the populations in each given loci.
While the null hypothesis stated there was no significant difference in the frequency of phenotypes between the snail populations found in our two sampling locations, our alternative hypothesis states that there is a significant difference between the differences in shell colour and shell pattern between snail population in woodland and shrubs, The samples were collected and statically analysis was performed to produce data which would identify if the null hypothesis was true or very unlikely.
References:
Jones, J. S., B. H. Leith, and P. Rawlings. "Polymorphism in Cepaea: A Problem with Too Many Solutions?" Annual Review of Ecology and Systematics 8.1 (1977): 109-43. Web. 12 Nov.